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cos(pi/65)cos((2pi)/65)cos((4pi)/65)cos(...

`cos(pi/65)cos((2pi)/65)cos((4pi)/65)cos((8pi)/65)cos((16pi)/65)cos((32pi)/65)=1/64`

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`cos(pi/65)cos((2pi)/65)cos((4pi)/65)cos((8pi)/65)cos((16pi)/65)cos((32pi)/65)`
`=frac{2sin (frac{pi}{65})}{2sin (frac{pi}{65})}cos(pi/65)cos((2pi)/65)cos((4pi)/65)cos((8pi)/65)cos((16pi)/65)cos((32pi)/65)`
`=frac{2sin (frac{2pi}{65})}{2 xx 2sin (frac{pi}{65})}cos((2pi)/65)cos((4pi)/65)cos((8pi)/65)cos((16pi)/65)cos((32pi)/65)`
`=frac{2sin (frac{4pi}{65})}{2 xx 4sin (frac{pi}{65})}cos((4pi)/65)cos((8pi)/65)cos((16pi)/65)cos((32pi)/65)`
`=frac{2sin (frac{8pi}{65})}{2 xx 8sin (frac{pi}{65})}cos((8pi)/65)cos((16pi)/65)cos((32pi)/65)`
`=frac{2sin (frac{16pi}{65})}{2 xx 16sin (frac{pi}{65})}cos((16pi)/65)cos((32pi)/65)`
`=frac{2sin (frac{32pi}{65})}{2 xx 32sin (frac{pi}{65})}cos((32pi)/65)`
`=frac{sin (frac{64pi}{65})}{64sin (frac{pi}{65})}` ...
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